Two main cast members of The L Word, Katherine Moennig and Erin Daniels, appear in Dexter. Erin Daniels appears in season one as Rita’s neighboor with the yapping dog, and Katherine Moennig is Michael Angelo, Vince Masuka’s tattoo artist in season five. Coincidentally (or not), Erin Daniel’s character is divorced and Katherine Moennig’s character is a lesbian.

Dexter’s two separate worlds collide when Astor and a friend break into the family house where Dexter is keeping Lumen; on top of that, Miami Metro knows Dexter is seeing Jordan Chase in search of ways to cope with Rita’s death. When Dexter steps up as a father to protect Astor and her friend, Harry admits that perhaps he overlooked the humanity within him, begging the question . . . was Dexter born to be a serial killer, or made into one?

Dexter is determined to keep his life compartmentalized so that his after-hours vocation cannot bleed into his everyday life (and ultimately so that an accident like Rita’s never happens again). Although he believes that Lumen is no longer his problem, she calls him and tells him she needs help disposing of a body: she shot one of her assailants. Miami Metro is called there and nearly catches Dexter in the middle of his mess; however, he manages to weasel his way out of it as he usually does. Dexter promises to help Lumen avenge her attackers because he cannot “get revenge for Rita’s death.” Lumen even starts to become a partner to Dexter, someone he cannot help but get attached to. The Santa Muerte killers are tracked down in the Mayan Club and Deb finally shoots one in the head to put a stop to it.

Lumen has become a problem, given the fact that she doesn’t trust Dexter, nor does she plan on leaving Miami any time soon, at least not until justice is served. Deb and Quinn’s romantic entanglement deepens; the Santa Muerte killers are still at large; and Quinn hires a guy busted by I.A. to look into Dexter Morgan for him after being suspended from work for approaching the Mitchells about Kyle Butler’s identity. Meanwhile, Dexter continues to worry about Harrison’s well-being after witnessing Rita’s death.

Dexter decides that he “[doesn’t] have time” to deal with the six stages of grief, nor does he have time for the FBI, who are still waiting for a statement from him as to what happened that day. Just when things seem to be settling down, Astor gets upset and decides that she wants to live with her grandparents (Paul’s parents) in Orlando. Harry tries to persuade Dexter to focus on his family rather than to satiate his Dark Passenger; however, the crisis counselor suggests that Dexter take some personal time and take care of himself. Deb finally deals with the fact that she and Quinn slept together in the heat of the moment. Dexter is now after Boyd Fowler after discovering blood spatter residue in the back of his moving truck. In a scramble to close the Trinity Killer case, the Mitchells are called upon to get a sketch on this “Kyle Butler” figure, which Quinn believes could be Dexter, launching an (informal) investigation of his own on Miami Metro’s own beloved blood spatter analyst.

In the aftermath of Trinity’s revenge, Dexter tells the first responders that Rita is dead and “it was me.” He asks Deb to treat Harrison like her own son, and she agrees to help raise him. Dexter decides that his family is better off without them after Astor and Cody take the news of their mother’s death poorly (and understandably so). Believing that Harry has abandoned him, Dexter sets fire to the shipping container with all of his belongings in it and destroys all digital files he once used to track down and kill his victims. Planning to make a break for it and leave, Harry finally reappears to him to tell him that his family – Astor, Cody, Harrison, and Debra – needs him. Meanwhile, Quinn is becoming even more suspicious of Dexter.

The season five premiere is supposed to take place the day after the season four finale. In spite of this, Detective Joey Quinn appears several pounds lighter and has a different haircut. Debra’s hair has grown a few inches. (Source)